According to Reuters, the researcher's lawyers issued a statement on his behalf on September 11, but did not identify him.

"I feel compelled to respond to media allegations that I am a 'Chinese spy,'" the lawyer quoted him as saying. The statement stressed: "I am completely innocent... I have dedicated my career to making people aware of the challenges and threats" from China.

The comments came after London's Metropolitan Police said on 10 September they had arrested two men in March on suspicion of offences under Section I of the Official Secrets Act 1911, which punishes offences deemed "prejudicial to the safety or interests of the state". The Sunday Times reported that one of them was a parliamentary researcher.

Police said two suspects have been released on bail until early October. The second person has not commented publicly.

The incident comes as Britain and China hope to restore relations after a series of tensions in many areas.

British Chancellor Rishi Sunak said he raised "very strong concerns about any interference in our parliamentary democracy" during a meeting with Chinese Premier Li Qiang at the Group of 20 (G20) summit on September 10.

The Chinese embassy in the UK said the allegations were fabricated. "The so-called claim that China is suspected of 'stealing British intelligence' is a complete fabrication and malicious slander," the embassy stressed.